Sling Mount - REAR - works wit the Magpul ASAP for optimal shoulder transitioning in one-point mode as well as the SGA Receiver Sling Mount. Also compatible with many snap-hook style sling loops and standard or QD sling swivels. FRONT - Compatible with the Magpul RSA, MSA, and Forward Sling Mount, as well as many snap-hook style sling loops and standard of QD sling swivels for use in two-point mode.